Saturday, January 16, 2016

There's been quite a few developments with Prism in the past few months, though again a lot of them are "under the hood" and not particularly visual. A lot's been done to improve stability at higher CPU speeds, and there's also been a large amount of refactoring of Prism's microcode to make it easier to work on and add new features.

Over Christmas, I did a lot of compatibility testing (also known as just playing games), as well as some playing around with palettes...

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Gauntlet II with a modified palette

Of course it wasn't ALL playing games and refactoring... I did do some work on adding new features, including Radstian mode (a 128x192 16 colour "chunky" mode with no colour clash). I also started adding César Hernández Bañó's additional screen modes (similar to Radstian mode but with different resolutions)

I've also been working on a boot rom, based on a test ROM that César Hernández Bañó created. I'm re-learning Z80 after a break of several years, so César has been increadibly helpful, thanks mate! The boot ROM lets you chose which ROM you want to boot to, and lets you set a couple of options. It also displays the Prism logo which is based on a mock-up which Andrew Owen created for me a while ago. You can probably guess where I got the idea from ;)

Shine on, you crazy ROM selector.

The boot rom utilises Prism's 16 colour (4 plane) clashless mode and as you can see it also departs from the Spectrum's standard colours - for example non-bright yellow's orange.